Do not check it; two laptops ARE allowed by TSA (though I don't know about where you are going, other countries, etc.). A way to TRY to avoid paying duty is to remove it from the original packaging and carry it on as you would any other laptop - I often carry my personal and work laptops for extended trips. Then you can send all of the documentation that comes in the box separately.

If you do check it, please let us know the result. You might have to join me in posting about checking the "uncheckable" at this thread:
http://www.flyertalk.com/forum/trave...r-made-36.html

Happy travels!